变宽连续钢箱梁桥计算模型比较分析

Analysis and Calculation Method of Steel Box Girder with Variable Width

厦门第二东通道互通主线桥为4×90 m大悬臂变宽度宽幅连续钢箱梁桥。主梁采用单箱多室斜腹板箱形截面,箱室从单箱七室变至单箱五室。变宽度钢箱梁桥作为异型桥的空间结构体系,结构复杂且受力状态上具有明显的空间效应。通过对比梁格法和板壳模型的计算结果,探究基于梁格法计算分析变宽度钢箱梁桥受力状态和结构变形的可靠性和合理性。结果表明:与板壳模型相比,梁格法能够较为准确计算变宽度钢箱梁桥在纵桥向和横桥向的应力大小、应力分布状态、支座反力及结构变形,平均误差在10%以内;在偏载作用下,梁格法能较好地反映结构的空间受力特征,表明采用梁格法计算分析变宽度钢箱梁桥能够满足工程要求。

The main interchange bridge of Xiamen Second East Passage is a 4×90 m width-varying continuous steel box girder bridge with large cantilever.The single-box and multi-cell steel box cross-section with inclined webs is adopted as the section of the main girder,in which the cells of cross-section change from single box 7 cells to single box 5 cells.The variable width steel box girder bridge,as the spatial structure,is a specialshaped bridge with complex configurations and has an obvious spatial effect of stress distribution.This paper compares the computing results of the grillage analytical method with those of the finite element model and discusses the reliability and rationality of stress distribution and structural deformation of the variable width steel box girder bridge calculated by the grillage analytical method.The results show that the longitudinal and transverse stress level,stress distribution,support reaction and structural deformation of the variable width steel box girder bridge can be accurately computed by the grillage analytical method with the average error within 10%,compared with the finite element method.Moreover,the grillage analytical method can predict the spatial effect under eccentric loading.It illustrates that the grillage analytical method can be applied to analyze the variable width steel box girder bridge so as to satisfy the engineering requirements.